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<div class="moz-cite-prefix">Beams and column members are rarely
given safety factors - rather they are rated for deflection.
Failure in a connector or hardware item is just that - failure
being torn apart, crushed, etc. - failure in a beam or column is a
function of deflection. If you're planning something, best to use
1/360 of span, which, for all practical purposes, is a safety
factor over 1/180 of span of about 2. Deflection ratios are based
somewhat on usage - 1/360 being ideal for flat office/living
room/occupied floors, 1/180 being tolerable for such things as
warehouse racks, etc., where a bit of sag doesn't bother what's
riding on them.<br>
<br>
Patrick<br>
<br>
On 2/26/2015 2:54 PM, Stephen Lee via Stagecraft wrote:<br>
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cite="mid:CAEqUiQ5OvicVWZDzsGSeF8yKzt8aDCxP6PVGyu+FAkPQrfP=YA@mail.gmail.com"
type="cite">
<p dir="ltr"><br>
Yes, I believe we're talking about the same concept.</p>
<p dir="ltr">My confusion is coming from a lot of the other load
ratings in the catalog having a safety factor mentioned. For
example, page 67 lists some crush load ratings, and lists a
safety factor of 2.5 (which I assume means that the actual
tested minimum load before failure is 2.5 times the stated
maximum allowable load).</p>
<p dir="ltr">Page 80 for general fittings says "Design load data,
where shown, is based on the ultimate strength of the connection
with a safety factor of 2.5, unless otherwise noted".</p>
<p dir="ltr">The pipe hangers on page 128 list a safety factor of
5, etc...</p>
<p dir="ltr">However, the max loads for the strut itself don't
have a safety factor listed. I kind of doubt that the loads they
have listed are the ultimate failure strength, but it doesn't
say one way or the other.</p>
<p dir="ltr">There's gotta be something I'm missing...</p>
<p dir="ltr">Stephen Lee<br>
</p>
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<pre class="moz-signature" cols="72">--
G. Patrick McCreary
Technical Director
Department of Theater and Dance
Indiana University of Pennsylvania</pre>
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